Explosively actuated pusher power tool



Nov. 5, 1968 JIBRACK EXPLOSIVELY ACTUATED PUSHER POWER TOOL 4 Sheets-Sheet 1 Filed March 4, 1966 lug.

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EXPLOSIVELY ACTUATED PUSHER POWER TOOL Filed March 4, 1966 4 Sheets-Sheet 4 3 73 B 25 M 5P J5 United States Patent 3,409,197 EXPLOSIVELY ACTUATED PUSHER POWER TOOL Jacques Brack, Nyon, Switzerland, assignor to ETEM,

Etablissement de Techniques Modernes, Vaduz, Liechtenstein, a company'of Liechtenstein Filed Mar. 4, 1966, Ser. No. 531,965 priority, application Switzerland, Mar. 8, 1965, 3,149/65; Aug. 9, 1965, 11,150/65 17 Claims. (Cl. 227-10) Claims ABSTRACT OF THE DISCLOSURE An explosively actuated power tool for driving fastening elements such as bolts, plugs, spikes, and nails, into a hard and compact material. The tool includes a barrel having a loadingchamber for receiving a cartridge and means for closing the chamber and guide means disposed forwardly of the barrel and a guide piece having a bore to receive and guide the fastening element. A piston slides in said barrel and in guide means and in said guide piece and is driven forwardly when the cartridge is fired to drive the fastening element. The rear assembly and the guide piece are displaceable relative to each other and relative to the axis of the tool so as to permit access to the loading chamber and to the guide piece for the introduction of a cartridge and the introduction of a fastening element.

r The present invention concerns explosively actuated power tools of the'type having a pusher or piston rod for driving of fastening elements such as bolts, plugs, nails and the like into hard and compact materials. Various embodiments of this type of tool exist but there are numerous disadvantages, one of which is the complexity and a certain fragility incompatible with the use of the tool. In addition such tools are usually expensive and in some cases difiicult to manipulate.

An object of the present invention is to provide a tool from driving fastening elements which obviates or substantially reduces the disadvantages of prior tools of this type. Another object of the invention is to provide a power driven tool for driving fastening elements which is inexpensive to manufacture and ruggedly constructed and may be readily operated. 7

Two embodiments of a tool embodying the invention are hereinafter described in conjunction with the accompanying drawings:

In these drawings:

FIG. 1 is a part sectional elevation of the assembly of one embodiment of the tool, before the firing of a fastening element.

' FIG. 2 is a cross section-substantially on the line IIII of FIG. 1.

FIG. 3 is a cross section substantially on the line III III of FIG. 1.

FIG. 4 is a partial axial section of the forward portion of the tool.

FIG. 5 is a similar view to FIG. 4 showing the ejection of a spent cartridge.

FIG. 6 is a view similar to that of FIG. 4 showing the loading of a cartridge and the positioning of a bolt.

FIG. 7 is a front elevation of a variant of a guide piece.

FIG. 8 is a front elevation of another form of the guide p1ece.

FIG. 9 is a part section elevation of a second embodiment of the tool in a loaded condition.

FIG. 10 is a front elevation of a detail of the tool.

FIG. 11 is a plan view of a yoke on which the barrel of the front part of the tool is pivoted. FIG. 12 is a part section of the front part of the tool after firing, but applied against a wall into which a bolt has just been driven.

3,409,197 Patented Nov. 5, 1968 FIG. 13 is a view similar to FIG. 12 on the return to the firing position of the piston rod and the ejection of a spent cartridge.

FIG. 14 is a view similar to FIG. 12 showing the loading of the cartridge and a fastening element.

FIG. 15 is a view in part section of a variation of the mounting of a guide socket on the front of the barrel.

A front part B of the tool is connected to the rear part A in a manner referred to below. The front part B includes a barrel 4 whose bore, at the end adjacent the part A, forms a loading chamber 5 adapted to receive a cartridge C. The barrel 4 is provided with a hard lining 6. An annular enlargement 7 on the liner 6 has a'frustoconical inner surface. The barrel'4 is mounted by trunnions 8 between the arms 9a of a yoke 9 whose body 9b is constructed to serve as the closure member for the loading chamber 5. The yoke 9 is pivotably mounted in a known manner on the rear part A of the tool. i

The barrel 4 has at its forward end an annular portion 4a provided with an internal thread which is complementary to external threads formed on a socket member 10. A pair of circumferentially spaced prongs 10a extend to the forward extremity of the socket member. Slots 11 are provided between the prongs 10a as best shown in FIG. 2. These prongs provide guide members which are parallel to the axis of the barrel 4.

' A collar 12 on the rear portion of the socket member 10 provides support for a spindle 13 which extends parallel to the axis of the barrel 4. A stop member 14 is provided at the forward end of the spindle 13. The spindle 13 provides support for a guide piece 15. The guide piece has a body portion 151: and the exterior surfaces thereof are of cylindrical shape adapted to be accommodated between the prongs 10a. Arms 15b project diametrically from the body portion 15a. A sheath 17 lines the bore 16 which extends through the body portion 15a. An annular flange 17a on the sheath 17 abuts a resilient ring 18 which is accommodated in an annular recess 19 formed in the body portion 15a. The ring serves as a shock absorber. One arm 15b has an opening therethrough receiving the spindle 13. The guide piece 15 may be moved longitudinally on the spindle 13 and the body portion 15a moves between the prongs 10a. The arms 15b are then accommodated in the slots 11. A helical spring 20 surrounding the spindle 13 between the stop member 14 and one arm of the guide piece 15 serves as a shock absorber. The guide piece may be rotated about the axis of the spindle 13 when itis moved forwardly beyond the free ends of the prongs 10a.

A piston rod 21 has a rear portion arranged for sliding movement in the bore of the barrel 4 and a forward portion adapted to slide in bore of the sheath 17. A piston shaped part 21c on the piston rod is slidable in the passage provided between the inner concave faces of the prongs 10a. 7

The connecting rod 21 has a length such that it will always be supported at least at two spaced zones 'on its length. As shown in FIGS. 1 and 6 the piston rod is supported by its parts 21a and 210. Whilst the piston rod is moving fowardly it is supported in each of its three parts 21a, 21b and 210, and at the termination of its forward movement it is supported by its parts 210 and 21b (FIG. 4). The length of the rear part 21a of the piston rod is furthermore such that when pushed to its rearmost position by means of rearward movement of the guide piece 15 it enters the loading chamber 5 to expel a cartridge C (FIG. 5) and thus functions as an ejector. In order to maintain the piston rod 21 in the charging position and in readiness to fire, the piston shaped part 21c is attached to the rear part 21a by a frusto conical portion 21d whose shape corresponds to that of the flared mouth of the bore of the liner 6. The length of the part 21a of the piston rod 3 is also, such that theintroduction of a cartridge C into the loading chamber 5, and the closure of the breech by the member 9b causes the piston rod 21 to move forwardly for disengaging the part 21d from the frusto conical bore at the forward end of the liner 6.

In order to load the tool the guide piece 15 is moved forwardly and is disengaged from the guide passage formed by the two prongs 10a during which operation the spring 20 is compressed. The guide piece can then be rotated around the spindle 13 and brought into the position shown in FIG. 6 in order that a bolt or the like D can be loaded into the bore of the guide piece from the rear and in the direction of the arrow F. A retaining flange d on the bolt fits into a corresponding groove 17b in the annular flange 17a.

The guide piece 15 may now be rotated on the spindle 13 and its bore realigned with the axis of the tool as shown in FIG. 1. As shown in FIG. 6 the front assembly B of the tool may be pivoted around the trunnions 8, in relation to the yoke 19 (which remains aligned in the rear part A of the tool) to uncover the loading chamber 5 into which the cartridge C may be introduced in the direction of the arrow F. The loading chamber is reclosed by returning the assembly B into alignment with the yoke. During this latter movement of the assembly B the curvature of the yoke body 9b causes the cartridge to be forced into the breech and this force causing suflicient axial movement of the piston rod 21 to release its conical portion 21d from the conical mouth of the bore of the barrel. The forward end of the piston rod is thus moved into contact with the rear end of the bolt.

When the cartridge is fired by a firing pin P (FIG. 12) the propellant gases drive the piston rod 21 forwardly, which forces the bolt D into the material M as shown in FIG. 4. The forward movement of the piston rod is arrested by the piston shaped part 21c when the latter abuts the annular flange 17a and the residual energy from the explosion is applied to the shock absorber 18. After driving the bolt D all that is required is to pivot the assembly B on the trunnions 8 and to push back the guide piece 15. This moves the piston rod 21 rearwardly and ejects the spent cartridge and wedges the cone 21d in the conical mouth of the bore of the barrel. This wedging of the cone 21d does not hamper the re-loading of the tool and the piston rod does not fall completely away from the tool when the guide piece is in the position shown in FIG. 6.

In the variation shown in FIG. 7 the guide piece, here marked 115, does not have any bulge corresponding to the body 15a. The guiding being then ensured solely by the spindle 13 and by the longitudinal slots 11.

The variation shown in FIG. 8 pertains to a guide piece, here marked 215, constructed with a plurality of bores 16 for example four, which allows the loading of a plurality of bolts capable of being brought successively into alignment with the axis of the barrel and to be fired successively.

The rear part A in the embodiment shown in FIGS. 9 to 14 is attached to a front assembly B1 which includes a barrel 24. The rearward portion 24a of the barrel communicates with a loading chamber 25 adapted to receive a cartridge C. The barrel 24 is pivotally mounted to turn about a transverse axis 26 between arms 27a and 27b of a yoke 27 whose base 27c serves as a closure member for the loading chamber 25 and also serves to hold the cartridge C tightly in the loading chamber. The arms 27a and 27b of the yoke 27 are of unequal lengths (FIG. 11). The branch 27a supports one end of the pivot pin 26 about which the barrel can be moved. The branch 27b does not support the pivot pin 26 and has such a length that when the assembly B1 is aligned with the rear part A of the tool the barrel is held tightly in the transverse direction between the two arms of the yoke 27 but when the front part B1 is pivoted through 90 the assembly B1 can be withdrawn from the said yoke 27 by simple transverse displacement.

The rearmost face of .the yoke 27.-.ab.uts .an.annular shock absorber 30 which inturn is supported by safety spring 32. A washer 31 is interposed between the spring 32 and the shock absorber 30.

The forward end of the barrel 24 carries guide means in the form of a socket member 28 whose forward end is fitted with an internal annular boss 28a. Slots 28b are located at diametrically opposite areas in the socket member 28. 1

The rearmost part of the socket member 28 is screwed onto a split nut 38. The two parts 38a and 38b of the split nut are held together by cotter pins 380 as shown in FIG. 10. The nut 38 is adapted to slide on the forward portion of the barrel 24 and to abut an annular shock absorber 39. The shock absorber ring 39 is accommodated between an annular flange 24c and the nut 38. The shock absorber 39 forms an abutment at the forward end of the barrel 24.

'Due to the particular arrangement of its forward portion the socket member 28 acts as a resilient gripper-and constitutes a guiding means for a piston shaped part 29a on the piston rod 29 whose rearward portion-29b is adapted to slide in the bore of the barrel. The forward end 290 of the piston rod 29 is adapted to drive a bolt D. The part 29a is located between the parts 29b and 29c and a frusto-conical portion 29d is adapted to wedge itself temporarily in a corresponding enlargement 24b of the bore 24a to hold the piston rod in position for loading a cartridge and a bolt. The socket member 28 serves as a guide for a slidable block 33 having a bore which corresponds to the diameter of the forward part 29c of the piston rod 29. Provided on the block 33 is an annular shoulder 33b which is adapted to be guided by the inner surface of the socket member 28. The block 33 serves as a housing for a ball 34 of a ball and socket joint. The ball 34 is mounted on a rear end of a guide piece 35 adapted to receive the bolt D to be driven into a wall M. The forward end of the guide piece 35 terminates in a frusto conical head 35a whose periphery cooperates with and is held by an operating sleeve 36 slidably mounted on the socket member 28. The sleeve 36 is provided with a ring 37 carried in an annular groove formed in an annular flange 36a on the rearward end of the sleeve 36.

In order to load the tool its parts are brought into the position shown in FIG. 14 and access is possible to the loading chamber 25 and to the rear end of the guide piece 35, whereby a cartridge C and a bolt D may be positioned respectively. The piston rod 29 is held in position by frictional contact between the frusto-conical surfaces 24b and 29d. The operating sleeve 36 is now slid forwardly which serves to align the guide piece 35, containing the bolt D, with the longitudinal axis of the tool.

The part B1 is pivoted to align it with the-axis of the cover and this action causes the cartridge C to be firmly positioned in the loading chamber 25. The portion 270 of the yoke also forces the piston rod forwardly torelease the conical surfaces 24b and 29d.

On firing, the piston rod 29 moves from the position shown in FIG. 9 to that shown on FIG. 12. At the end of the stroke of the piston shaped part 29a comes into contact with the block 33. The piston rod is initially braked by the wall itself without assistance from the other pieces of the tool. This is made possible due to the construction of the parts of the tool which ensures that the boss 28a and shoulder 33b become disengaged.

When the piston rod has been braked as described the boss' 28a and shoulder 33b come into contact which causes the socket member 28, to compress the shock absorber 39. This action constitutes a second braking or damping of the piston rod.

To further absorb shock there is a third braking phase, and this is constituted by the annular shoulder 33b overrunning the inner boss 28a of the socket member 28.

The absorption of energy is such that the pieces 33 and 35 move out of the sleeve slowly, account being taken of the fact that these pieces are carried out as a function of the power of the most powerful cartridge used in the tool.

In the exceptional case in which the third phase of braking mentioned above should prove insufficient, a fourth braking phase comes into force and this is constituted by the periphery of the piston shaped part 29a of the piston rod 29 coming into contact with the boss 28a which then acts a second time on the shock absorber 39. It is also possible in an extreme case that the boss 28a may be overrun by the periphery of the piston shaped part 29a and this would cause further retardation.

After firing and the pivoting of the front part B1 in relation to the rear part A a push in the direction of the arrow Fa (FIG. 13) ejects the spent cartridge C. At this moment the tool is ready to be reloaded.

It will be appreciated that in this second embodiment, the interaction between the piston rod and the ammunition is the same as that referred to in the embodiment of FIGS. 1 to 6.

FIG. 15 shows a simplified variation wherein the socket member 28 is screwed directly onto the barrel 24.

The above description and the accompanying drawings show the simplicity of the driving-in tool, a simplicity which imparts great robustness, ease of maintenance, use and manufacture. Interchanging of parts subjected to wear is simple, due to the absence of accessories such as pins for placing the bolts in position as is necessary in some appliances of a similar type. In addition the cartridge and bolt are positioned from the rear, that is in the direction of firing.

It should be appreciated that the embodiments of the tool described above and shown on the annexed drawing are given by way of example only and that any modification in detail may be made therein without departing from the scope of the invention as defined by the appended claims.

What I claim is:

1. In an explosively actuated power tool for driving a fastening element, a rear assembly, a front assembly movably secured to said rear assembly, a barrel having a loading chamber at the rear end for receiving a cartridge, means for closing said chamber, guide means disposed forwardly of said barrel and attached to the forward end of the barrel, a front guide piece having a bore for receiving and guiding said fastening element disposed forwardly of said barrel and adapted to slide relative to said guide means, a piston rod slidable in said barrel and in said guide means and in said guide piece, said rear assembly and the front guide piece being displaceable relative to each other and relative to the axis of the piston rod to provide access to said loading chamber and to the rear of said guide piece for the introduction of a cartridge behind the piston rod and the introduction of a fastening element in front of the piston rod.

2. An explosively actuated power tool as set forth in claim 1 including a spindle positioned parallel to the axis of said barrel, means securing the rear end of said spindle to said barrel, said guide piece being rotatable about said spindle to displace it with respect to the axis of the piston rod.

3. An explosively actuated power tool as set forth in claim 1 including a block slidably in said guide means and having a bore co-axial with the bore of said barrel for guiding said piston rod, pivot means connecting said guide piece to said block whereby the guide piece is pivoted relative to said barrel, an operating sleeve slidable on the guide means whereby the operating sleeve in its forward position aligns the guide piece with the block and with the axis of the barrel and when the operating sleeve is at its rearward position the guide piece may be pivoted to enable the fastening element to be introduced into the bore of said guide piece.

4. An explosively actuated power tool as set forth in claim 2, wherein the forward. end of the spindle is provided with a stop member and a shock absorber is mount ed intermediate said stop member and said guide piece.

5. An explosively actuated power tool as set forth in claim 1 wherein the piston rod includes a rear. portion slidable in said barrel and a front portion slidable in said guide piece and a piston shaped part slidable in said guide means for abutting against the rear part of the guide means and abutting the rear end of the guide piece, the length of the guide means and the lengths of the two portions of said piston rod being such that the rod is supported at least at .two spaced apart positions along its length.

6. An explosively actuated power tool as set forth in claim 2 including a sheath within the bore of said guide piece having an annular flange at its rear end, and a shock absorber disposed between said annular flange and said guide piece.

7. An explosively actuated power tool as set forth in claim 3, wherein the pivot means connecting the guide piece to said block is in the form of a ball and socket joint.

8. An explosively actuated power tool as set forth in claim 3, wherein the operating sleeve has an internal annular groove, and a lining within said groove frictionally engaging said guide means.

9. In an explosively actuated power tool for driving a fastening element, a rear assembly, a front assembly movably connected to the said rear assembly, a barrel having a loading chamber for receiving a cartridge, means for closing said chamber guide means disposed forwardly of said barrel and secured thereto, a front guide piece having a bore for receiving and guiding said fastening element, said guide piece being mounted to slide relative to and be positioned in said guide means, a piston rod slidable in said barrel and in said guide means and in said guide piece, and said guide means comprising a socket member having a forward extremity split longitudinally of the socket member.

10. An explosively actuated power tool as set forth in claim 9, wherein the forward extremity of the split socket member is of-smaller diameter than other portions of the socket member.

11. An explosively actuated power tool as set forth in claim 9, in which the forward extremity of the split socket member is provided with an internal annular boss.

12. An explosively actuated power tool as set forth in claim 9, wherein the rear end of said socket member is slidably mounted relative to said barrel, and an annular shock absorber interposed between said barrel and said socket member.

13. In an explosively actuated power tool for driving a fastening element, a rear assembly, a front assembly movably connected to said rear assembly, a barrel having a loading chamber at its rearward extremity for receiving a cartridge, closure means whereby said chamber may be closed, guide means disposed forwardly of said barrel and attached to the forward end thereof, a front guide piece having a bore for receiving and guiding a fastening element, said guide piece being disposed forwardly of said barrel and adapted to slide relative to said guide means co-axially of the barrel, a piston rod adapted to slide in said barrel and in said guide means and in said guide piece, said piston rod being of such dimensions longitudinally relatve to said barrel that it may be positioned in direct contact with a cart-ridge located in the loading chamber whereby rearward movement of the piston rod serves to initiate ejection of the cartridge.

14. An explosively actuated power tool as set forth in claim 13 including retaining means maintaining said piston rod in its extreme rearward position, and said closure means being shaped to urge a cartridge into the loading chamber and to move said piston rod forwardly and disengage it from said retaining means.

15. An explosively actuated power tool as set forth in claim 14, wherein the retaining means includes a frustoconical part on said piston rod adapted frictionally to engage a flared mouth in the barrel.

16. An explosively actuated power tool as set forth in claim 11 wherein the means for closing the chamber comprises a yoke to which the barrel is pivoted, and shock absorber means positioned rearwardly of said yoke.

17. An explosively actuated power tool as set forth in claim 16, in which the yoke has arms of different lengths,

said barrel being pivotable about a transverse axis of the 10 longer of said arms, said other arm being of sufficient length to support said barrel which upon pivoting through approximately 90 may be displaced transversely of the tool.

References Cited TRAVIS S. MCGEHEE, Primary Examiner. 

